Systematic reviews of TCM trials: how does inclusion of Chinese trials affect outcome?

Systematic reviews (SRs) are an important tool for the synthesis of research and are used to guide both research and clinical practice. Previous research suggests that changes to standard SR methodology may be warranted. The objectives of this study were to determine the value of adding Chinese-language databases to conventional systematic review (SR) search strategies, and ii) to determine the importance of methodological validation of TCM RCTs in the conduct of SRs of two health conditions, chronic fatigue syndrome (CFS) and EBV-infectious mononucleosis (mono).

Ten English-language and two Chinese-language databases were searched from inception to 2008. After initial screening potentially relevant publications were retrieved and assessed based on predetermined inclusion criteria. Method of randomization was verified using author interviews.

Mono Search - While English-language database searches did not yield any potentially relevant references, Chinese-language database searches identified 14 studies labelled as RCTs. Author interview determined that 10 were clinical summaries and one a controlled clinical trial. Authors for three publications were unavailable. CFS Search - English-language and Chinese-language database searches identified 8 and 28 potentially relevant references, respectively, for a total of 36, however, none met all inclusion criteria.

Utilization of Chinese-language databases greatly increased the number of potentially relevant references for each search. Unfortunately, due to methodological flaws, this additional information did not generate any usable information. Medical research in China continues to be active, including the conduct of RCTs, however, improvements in trial design and conduct in medical research in China are essential in order for this material to be useful in guiding research and practice.